Abstract
Background In obstetrics, accurately determining gestational age (GA) is a critical aspect of managing pregnancy and evaluating fetal growth and development. Intrauterine growth restriction (IUGR) is characterized by the failure of the fetus to reach its potential growth. Early detection of IUGR is crucial for optimal obstetric care to reduce fetal complications and neonatal morbidity and mortality. The purpose of the current research is to determine the role of transcerebellar diameter (TCD) and the TCD/abdominal circumference (AC) ratio in assessing fetal growth and diagnosing IUGR. Methods In the sample, there were 600 expectant mothers with GA exceeding 28 weeks. We measured TCD and AC and then calculated the TCD/AC ratio. We used IBM SPSS Statistics for Windows, V. 22.0 (IBM Corp., Armonk, NY), for statistical analysis. The data was subjected to statistical tests, including Pearson's correlation coefficient, coefficient of determination, and tests of validity. Results The current research demonstrates a strong linear correlation between TCD and GA. Additionally, there was no notable disparity in TCD measurements between normal and IUGR fetuses with the same GA. There was an insignificant relationship between the TCD/AC ratio and GA, with a constant TCD/AC ratio in the third trimester of pregnancy in normal fetuses. The mean TCD/AC ratio was 14.72±0.89 (mean±standard deviation), and a cut-off value of 16.5 was determined to diagnose IUGR. Conclusion TCD can serve as a reliable measure for GA estimation during the third trimester in pregnant women with uncertain last menstrual period (LMP) or no dating scan and IUGR fetuses. In diagnosing IUGR, the TCD/AC ratio has demonstrated greater sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV). The TCD/AC ratio is a GA-independent measure that can be used to diagnose IUGR.